如何对R中数据帧的几列应用统计测试

我想应用这个测试,而不仅仅是列 x1 ,正如我在本例中所做的那样,但在 df .在这种情况下 x1 和 x2 .

我试着把这段代码放在一个函数中,并使用 purrr::map 但我做不好。

library(tidyverse)

df <- tibble(skul = c(rep('a',60), rep('b', 64)),
             x1 = sample(1:10, 124, replace = TRUE),
             x2 = sample(1:10, 124, replace = TRUE),
             i_f = c(rep(0, 30), rep(1, 30), rep(0, 32), rep(1, 32)))


lapply(split(df, factor(df$skul)),
       function(x)wilcox.test(data=x, x1 ~ i_f,
                              paired=FALSE))
#> Warning in wilcox.test.default(x = c(10L, 5L, 8L, 4L, 6L, 3L, 10L, 2L, 10L, :
#> cannot compute exact p-value with ties
#> Warning in wilcox.test.default(x = c(3L, 3L, 4L, 9L, 8L, 10L, 5L, 5L, 4L, :
#> cannot compute exact p-value with ties
#> $a
#> 
#>  Wilcoxon rank sum test with continuity correction
#> 
#> data:  x1 by i_f
#> W = 546, p-value = 0.1554
#> alternative hypothesis: true location shift is not equal to 0
#> 
#> 
#> $b
#> 
#>  Wilcoxon rank sum test with continuity correction
#> 
#> data:  x1 by i_f
#> W = 565, p-value = 0.4781
#> alternative hypothesis: true location shift is not equal to 0
Created on 2022-04-13 by the reprex package (v2.0.1)